Interpenetrating hexagonal arrangements of sticks are a challenging mathematical exercise to assemble from pencils. Four different directions are used, as color-coded here. The above sculpture, 72 Pencils, has tiny dots of glue to hold itself together, but you can easily use eight rubber bands around the ends.The idea scales up to larger sizes very nicely, as can be seen in this version made by David Russell from three-foot long dowels.And what better way to celebrate the joys of mathematics than with a ritual conflagration!